Microhematuria

Patient Guideline Summary

Publication Date: July 23, 2020

Last Updated: March 3, 2023

Objective

This patient summary means to summarize key recommendations from the American Urological Association (AUA) and the Society of Urodynamics, Female Pelvic Medicine & Urogenital Reconstruction (SUFU) for microhematuria. This patient summary is limited to adults 18 years of age and older and should not be used as a reference for children.

Overview

Hematuria (visible blood in urine) is common. There is a type of hematuria called microhematuria where blood in urine is detected only by a microscope.

We will use the abbreviation MH throughout this summary to refer to microhematuria.

Nephrologic, kidney-related, and renal can be used interchangeably. Malignancy and cancer can be used interchangeably.

Some of the most common causes of MH are urologic, nephrologic (kidney-related), as well as gynecologic (diseases that are specific to women).

Malignancy is the cause of about 3% of MH.

This patient summary focuses on the diagnosis, evaluation, and follow-up of MH in order to find the 3% of cancers with the greatest efficiency.

Diagnosis and definition of microhematuria (MH)

Your doctor should define MH as more than 3 red blood cells per high-power field (RBC/HPF) on microscopic evaluation of a single, well-collected urine specimen.

Initial evaluation:

If you have MH, your doctor will perform a detailed history and physical examination to assess your risk for genitourinary malignancy, medical kidney disease, and gynecologic and non-malignant genitourinary causes of MH.
Your doctor will perform the same evaluation whether or not you are taking drugs that increase your bleeding tendency (such as aspirin, other antiplatelet agents, or anticoagulants) or not taking these drugs.
If you have findings that suggest a gynecologic or non-malignant urologic cause, your doctor will probably evaluate you with appropriate physical examination techniques and tests to identify the cause.
If you are diagnosed with a gynecologic or non-malignant genitourinary source of MH, your doctor will probably repeat the urinalysis (UA) following resolution of the gynecologic or non-malignant genitourinary cause. If MH persists or the cause cannot be identified, your doctor may perform a risk-based urologic evaluation.
If you have hematuria related to a urinary tract infection, your doctor will probably order a UA with microscopic evaluation following treatment to ensure the disappearance of the hematuria.
if you have continuing MH, your doctor may refer you to a uroligist for a risk-based urologic evaluation.

Risk stratification:
Following an initial evaluation, your doctor will probably categorize you as low-, intermediate-, or high-risk for genitourinary malignancy based on the following table.

AUA Microhematuria Risk Stratification System

Low (patient meets all criteria)	Intermediate (patient meets any one of these criteria)	High (patient meets any one of these criteria)
Women age <50 years; Men age <40 years Never smoker or <10 pack years 3-10 RBC/HPF on a single urinalysis No risk factors for urothelial cancer (see Intermediate column)	Women age 50-59 years; Men age 40-59 years 10-30 pack years 11-25 RBC/HPF on a single urinalysis Low-risk patient with no prior evaluation and 3-10 RBC/HPF on repeat urinalysis Additional risk factors for urothelial cancer Irritative lower urinary tract symptoms Prior pelvic radiation therapy Prior cyclophosphamide/ifosfamide chemotherapy Family history of urothelial cancer or Lynch Syndrome Occupational exposures to benzene chemicals or aromatic amines (e.g., petrochemicals, rubber, dyes) Chronic indwelling foreign body in the urinary tract	Women or Men age ≥60 years >30 pack years >25 RBC/HPF on a single urinalysis History of gross hematuria

* pack-year = smoking a pack of cigarettes a day for a year

Urinary tract evaluation

Low risk:

If you are at low risk for MH, your doctor will possibly offer you a choice of repeating UA within six months or proceeding with cystoscopy and renal ultrasound.

Initially low-risk with hematuria on repeat urinalysis (UA):

If you are a low-risk patient and initially chose not to undergo cystoscopy or upper tract imaging and have MH on repeat urine testing, you will probably be reclassified as intermediate- or high-risk. Hence, your doctor will probably perform cystoscopy and upper tract imaging.

Intermediate-risk:

Your doctor will probably perform cystoscopy and renal ultrasound If you are at intermediate risk for malignancy.

High-risk:

Your doctor will probably perform cystoscopy and imaging if you have MH categorized as high-risk for malignancy.
- Your doctor will probably discuss with you the different options for upper tract imaging in high-risk patients.
- Cystoscopy is a critical part of the work-up if you are at high-risk for bladder cancer because the earlier cancer is detected, the higher the chance of cure.
Your doctor will probably perform white light cystoscopy if you are undergoing an evaluation of the bladder for MH.
- Cystoscopy using different colored lights is sometimes used because some conditions are better seen than with white light.

If you have persistent or recurrent MH previously evaluated with renal ultrasound, your doctor may perform additional imaging of the urinary tract.

If you have MH and a family history of renal cell carcinoma (RCC) or a known genetic renal tumor syndrome, your doctor will possibly perform upper tract imaging regardless of the risk category.

Urinary markers

(A marker is a biological molecule in blood, other body fluids, or tissues that is a sign of a normal or abnormal process or a condition or disease)

AUA does not recommend using urine cytology or urine-based tumor markers in the initial evaluation of patients with MH.

It is possible to look for cancer cells in the urine, a test your doctor might order.

Follow-up

If you have a negative hematuria evaluation, your doctor may obtain a repeat UA within 12 months.

If you have a prior negative hematuria evaluation and subsequent negative UA, your doctor may discontinue further evaluation for MH.

If you have a prior negative hematuria evaluation and persistent or recurrent MH at the time of repeat UA, your doctor will possibly engage you in shared decision-making regarding the need for additional evaluation.

If you have a prior negative hematuria evaluation and develop gross (seen by eyes) hematuria, a significant increase in the degree of MH, or new urologic symptoms, your doctor will likely initiate a further evaluation.

Abbreviations

MH: Microhematuria
RBC/HPF: Red Blood Cells Per High-power Field
RCC: Renal Cell Carcinoma
UA: Urinalysis

Source Citation

Barocas DA, Boorjian SA, Alvarez RD, Downs TM, Gross CP, Hamilton BD, Kobashi KC, Lipman RR, Lotan Y, Ng CK, Nielsen ME, Peterson AC, Raman JD, Smith-Bindman R, Souter LH. Microhematuria: AUA/SUFU Guideline. J Urol. 2020 Oct;204(4):778-786. doi: 10.1097/JU.0000000000001297. Epub 2020 Jul 23. PMID: 32698717.

Disclaimer

The information in this patient summary should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.